Data imprinting device for a camera

ABSTRACT

A data imprinting device focusses light emitted from an array of LEDs onto the film, exposing the film as it is fed. A single chip microcomputer controls the LED array to imprint data. Some of the LEDs in the array are always energized together, while others are energized independently. The LEDs which are energized together require only a single control line, thus reducing the number of control lines, and consequently permitting reduction in the size of the camera. The group-wise serial activation of the dot matrix columns slightly staggers the imprinted data, but the imprinted characters are fully recognizable. In addition to reducing the number of control lines, the group-wise serial activation also reduces the peak load on the constant circuit, and thereby reduces the size of this circuit.

This is a divisional of application Ser. No. 08/119,712 filed on Sep.10, 1993, now U.S. Pat. No. 5,519,463.

BACKGROUND OF THE INVENTION

The invention relates to data imprinting devices for cameras whichimprint data, such as a date, on photosensitive film. More specifically,the invention relates to a data imprinting device which imprints byexposing a dot-matrix of points on a photographic film using an array oflight emitting elements activated synchronously with the feeding of thefilm.

Referring to FIG. 8, a data imprinting device 80, according to the priorart, employs seven light emitting diodes (LEDs) 1˜7 arrangedperpendicularly to a direction of feed of a film. A constant voltagecircuit 73 feeds power from a battery 71 to a motor drive circuit 37.Constant voltage circuit 73 provides a constant voltage output despitefluctuations in the voltage of battery 71. Constant voltage circuit 73supplies stabilized power to a CPU 17, a light emitting diode (LED)drive circuit 19 and a photo interrupter 53.

A partial pushdown switch SW1 and a full pushdown switch SW2 areconnected to CPU 17. Partial pushdown switch SW1 is actuated by partialdepression of a camera release button. Full pushdown switch SW2 isactuated by full depression of the camera release button. Output signalsfrom photo interrupter 53 are input to CPU 17. Outputs from CPU 17 areconnected to LED drive circuit 19 and motor drive circuit 37. A feedmotor 38, for feeding film, is driven by motor drive circuit 37.

Seven LEDs 1˜7 are connected to LED drive circuit 19. Seven outputterminals A1˜A7 of CPU 17 provide control signals on signal L1˜L7 tocorresponding input terminals B1˜B7 of LED drive circuit 19.

The control signals on signal lines L1˜L7 control counterpart LEDs 1˜7,respectively. Thus, control signals from signal line L1, for example,control signals input on signal line L2 cause LED 2 to emit light, andso forth.

Referring now to FIGS. 1, 8 and 9, numerals are formed by the dataimprinting synchronized with the feeding of film. Numerals are formed byactivating a combination of LED1˜LED 7 (FIG. 9), at successive intervalsof time for each numeral. The time intervals are keyed to the movementof the film as the film is fed. Dot matrix patterns are therebygenerated, each time interval mapping into a corresponding interval ofthe film. Data imprinting exposure takes place in five successive timeintervals A, B, C, D and E.

The blackened circles represent exposed regions on the film forformation of the numeric character "9". The white circles representregions on the film which remain unexposed in forming the character "9"during feeding of the corresponding interval of film.

In the conventional data imprinting device, each LED is connected to itsown signal line. Thus, to control operation of, seven LEDs 1˜7, forexample, seven signal lines L1˜L7 are required.

In addition, note that each column A through E represents an interval offilm that was fed past and exposed by LEDs 1˜7 at the same time.Therefore, up to 7 LEDs may be activated at a single time in order forthe character shown in FIG. 9 to be imprinted. Thus, the conventionalimprinting device must power all seven LEDs simultaneously. For example,when imprinting the points in column C for the numeral "1," seven LEDsare simultaneously lighted. If 20 mA of current is required to lighteach LED, the conventional device requires a constant-voltage circuithaving a capacity as large as 140 mA.

In view of the recent trend toward reducing the size of cameras, thespace required by components, such as signal lines and circuit elements,is a significant design issue. Thus, the ability to reduce the size,number and cost of components has positive implications for cameradesign.

A data imprinting device requiring fewer control signal lines would notonly reduce the number of components by the number of signal lines, butalso the size of the CPU. This is because the CPU requires fewer controlsignal outputs to drive a given number of LEDs. Thus, a camera employinga CPU with seven control signal outputs is inevitably larger and morecostly than one employing a CPU with fewer control signal outputs.

The ability to reduce the peak power requirements of the LED array overthat of a conventional device can also result in space and cost savings.

Another embodiment of a data imprinting device, disclosed in JapaneseLaid-open Patent Publication No. 4-81831, achieves a lower peak powerrequirement by activating the LEDs sequentially, so that fewer LEDs areactivated at a given time. But, in this device, the characters imprintedare slanted and difficult to read. In addition, successive LEDs in thisdevice are activated before previous ones are deactivated. The device,therefore fails to take full advantage of the possible peak powerreductions.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to reduce the size and numberof components required for a camera data imprinting device of prior artdesign.

It is a further object of the present invention to provide a camera dataimprinting device with fewer control signal output terminals and signallines compared to conventional devices.

It is a further object of the present invention to provide a camera dataimprinting device that require a lower capacity constant-voltage circuitthan conventional designs.

It is a still further object of the invention to provide a camera dataimprinting device capable of imprinting clear, recognizable characters.

Briefly stated, the present invention is a device for a camera thatimprints data such as a date, on photosensitive film. Light emitted byan array of LEDs is focused onto the film, exposing the film as it isfed. A single chip microcomputer controls the LED array to imprint data.Several lines connect the microcomputer to a LED driver circuit. Eachinput of the driver circuit corresponds to a single LED in the LEDarray. However, some outputs of the microcomputer chip are connected tomore than one input of the driver. Thus, the number of control linesrequired is less than the total number of LEDs used to form theimprinted data.

The microcomputer activates the appropriate LEDs in groups, each groupbeing activated consecutively. Thus, the maximum number of LEDsactivated at a given instant is equal to the maximum number of LEDs inthe group with the most LEDs.

The resulting imprinted characters therefore include points, lying inseparate rows, that are always imprinted, in concert. Also, because ofthe group-wise serial activation, the dot matrix columns of imprinteddata are somewhat staggered. Yet, the characters imprinted are veryrecognizable. The grouping of LEDs produces characters that are morerecognizable than those produced by prior art devices that employtemporal staggering to reduce peak power demand.

Because of the configuration and control of the data imprinting device,the number of CPU output terminals, signal leads and the peak demand ofthe LED are reduced. Additionally, the size of the microcomputer can bereduced relative to that of a conventional device because of the reducednumber of output terminals required. Moreover, the size of the constantvoltage circuit may be reduced relative to that of a conventional devicebecause of the reduced peak demand.

According to an embodiment of the present invention there is disclosed adata imprinting device for a camera comprising: a plurality of lightemitting elements, a control circuit, the control circuit includingmeans for producing a plurality of control signals, first means,responsive to one of the plurality of control signals, for controllingat least two of the plurality of light emitting elements and secondmeans, responsive to at least another of the plurality of controlsignals for controlling at least another of the plurality of lightemitting elements, independently of the at least two whereby reducedcontrol leads are provided.

According to another embodiment of the present invention there isdisclosed, a data imprinting device for a camera comprising: a pluralityof light emitting elements, a control circuit, the control circuitincluding means for producing a plurality of control signals, firstmeans, responsive to ones of the controls signals for controlling onesof the plurality of light emitting elements, second means, responsive toat least another of the plurality of control signals for controlling,for controlling at least another of the plurality of light emittingelements, independently of the ones and the control circuit includingmeans for producing a timing of controlling of the ones at a timenon-overlapping with the controlling of the at least another, wherebyreduced peak power demands are provided.

According to still another embodiment of the present invention there isdisclosed, a data imprinting device for a camera comprising: a pluralityof light emitting elements, a control circuit, the control circuitincluding means for producing a plurality of control signals, firstmeans, responsive to one of the plurality of control signals, forcontrolling at least two of the plurality of light emitting elements,second means, responsive to at least another of the plurality of controlsignals for controlling at least another of the plurality of lightemitting elements, independently of the at least two, the controlcircuit including means for producing a timing of controlling of the atleast two at a time non-overlapping with controlling of the at leastanother, whereby reduced control leads, and reduced peak power demandsare provided.

The above, and other objects, features and advantages of the presentinvention will become apparent from the following description read inconjunction with the accompanying drawings, in which like referencenumerals designate the same elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a data imprinting device according anembodiment of the present invention.

FIG. 2 is a circuit diagram of the data imprinting device of FIG. 1.

FIG. 3 is a schematic diagram showing a character imprinted by the dataimprinting device of FIG. 1.

FIG. 4 is a flow chart showing the photographing operation performed bythe data imprinting device of FIG. 1.

FIG. 5 is a flow chart showing a film take-up operation performed by thedata imprinting device of FIG. 1.

FIG. 6 is a flow chart showing a data imprinting operation performed bythe data imprinting device of FIG. 1.

FIG. 7 is time chart showing the temporal relationship between the FSSand the control signals governing each LED of the data imprinting deviceof FIG. 1.

FIG. 8 is a circuit diagram of a conventional data imprinting device fora camera.

FIG. 9 is a schematic diagram showing a character imprinted by the dataimprinting device of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1., a data imprinting device 10 for a camera is shown.A photosensitive film 31 contained in a film cartridge 33, is woundaround a spool 35. Feed motor 38 is actuated by motor drive circuit 37to drive spool 35.

An aperture frame 39, represented by double-dashed broken lines, is aregion of the film located directly behind an aperture of the camera.Thus, aperture frame 39 is the region of film 31 which is exposed when aphotograph is taken. An exposed frame 41, also represented bydouble-dashed lines, is a previously exposed region of film 31.

A film feed detector 43, for detecting the feeding of film 31 as it iswound, is located above aperture frame 39. Film feed detector 43includes a film feed detection roller 45 biased by a pressure leafspring 44 into contact with film 31. A disk-shaped encoder 49 isconnected, through a shaft 47, to film feed detection roller 45. As film31 advances, film feed detection roller 45 is correspondingly rotated.Encoder 49 is rotated the same amount as film feed detection roller 45.

Encoder 49 contains a number of radial slits 51. Encoder 49 is partlyinserted in photo interrupter 53. As encoder 49 rotates a light beamgenerated by photo interrupter 53 is alternately transmitted and blockedas each radial slit 51 passes beneath it. When the light beam istransmitted, it strikes a photodetector in photo interrupter 53 so thatphoto interrupter 53 output alternates between a high and a low level asencoder 49 rotates. Thus, photo interrupter 53 sends a train ofrectangular waves, called the film sensor signal (FSS), to a CPU 57 inresponse to rotation of encoder 49. The amount of film 31 that is fed isdetected by counting the number of signal level reversals of the FSS.According to the present embodiment, 360 FSS reversals are generatedduring the feeding of a single frame of film.

Signals from partial pushdown switch SW1 and full pushdown switch SW2are fed to CPU 57. A LED array 59, consisting of seven LEDs arranged ina straight line at specified intervals, is positioned in front of film31. A LED drive circuit 61, which is connected to CPU 57, controls theemission of light by each LED in LED array 59.

A focusing lens 63 directs light emitted by LED array 59 to a narrowfocal region 67 of exposed frame 41. Light, emitted from LED array 59,exposes film 31 in focal region 67 as film 31 is fed. LED array 59 isactivated according to a time-varying sequence under the control of CPU57. The activation of LED array 59 is synchronized with the feeding offilm 31 to occur within a specified range of feed of film 31. Thus, dotmatrix patterns of imprinted data 65 are formed.

Electrical contacts 68 read a conventional DX code 70, which indicatesthe number of exposed-photograph frames and the ISO sensitivity of film31, from film cartridge 33.

Referring now also to FIG. 2, data imprinting device 10 includes motordrive circuit 37 and constant voltage circuit 73 connected to battery71. Constant voltage circuit 73 stabilizes the supply of power byinsuring a constant voltage output despite fluctuations in the voltageof battery 71. Constant voltage circuit 73 supplies stabilized power toCPU 57, an LED drive circuit 61 and photo interrupter 53.

CPU 57 is preferably a single chip microcomputer that controls thesequence of operation of the camera. CPU 57 incorporates a FSS counterand a timer, whose operations are described below. Partial pushdownswitch SW1 and full pushdown switch SW2 are connected to CPU 57. Partialpushdown switch SW1 and full pushdown switch SW2 are actuated by partialand full depression of a camera release button respectively. CPU 57 isalso connected to LED drive circuit 61 and motor drive circuit 37. Feedmotor 38 is connected to motor drive circuit 37.

Seven LEDs 1˜7 comprising LED array 59 are connected to LED drivecircuit 61. FSS output of photo interrupter 53 is connected to an inputof CPU 57.

CPU 57 has five control signal output terminals C1˜C5 for applyingcontrol signals on signal lines D1˜D5 to LED drive circuit 61. The fivecontrol signals are connected to seven control signal input terminalsE1˜E7 on LED drive circuit 61, corresponding respectively to the sevenLEDs 1˜7.

The connection of five signal lines D1˜D5 to the seven control signalinput terminal E1˜E7 of LED drive circuit 61 is as follows. Signal lineD1 connects control signal output terminal C1 to control signal inputterminal E1. Signal line D2 from control signal output terminal C2 isconnected in parallel to control signal input terminals E2 and E3.Signal line D3 from control signal output terminal C3 is connected tocontrol signal input terminal E4. Signal line D4 from control signaloutput terminal C4 is connected in parallel to control signal inputterminals E5 and E6. Signal line D5 from control signal output terminalC5 is connected to control signal input terminal E7.

Thus, control signals from one of signal lines D1, D4 and D7 causes anemission of light from corresponding LED 1, 4 or 7. A control signalfrom signal lines D2 or D4 causes the emission of light from thecorresponding pair of LEDs, 1 and 2 or 5 and 6.

Referring now to FIGS. 1, 2 and 3, a numeral formed by the dot matrixpatterns generated by data imprinting device 10 are shown in FIG. 3. Theblackened circles represent exposed areas on film 31 constitutingimprinted data 65 to form the numeric character "9". The white circlesrepresent regions on film 31 that remain unexposed in forming thecharacter "9". A slight, but acceptable difference is seen between thecharacter "9" in FIG. 3, and the character "9" in the prior artcharacter "9" of FIG. 9.

As shown in FIG. 3, the activation of LEDs LED1˜LED7 occurs during fivesuccessive intervals in time, A, B, C, D and E, keyed to the movement offilm 31, to form each numeral. Each of the five successive timeintervals represents a range of times having three specific times duringwhich various subsets of LEDs LED1˜LED 7 may be energized. LEDsLED5/LED6 are always actuated together at the earliest of the threetimes in each interval. LEDs LED2/LED3 are always actuated together atthe latest of the three times in each interval. The time of actuation ofLED5/LED6 contains no overlap with the time of actuation of LED2/LED3.Independently controlled LED7 is actuated at the same times asLED5/LED6. Independently controlled LED1 is actuated at the same time asLED2/LED3. Independently controlled LED4 is actuated at a timeintermediate between the earliest and the latest time in each range.

Although the circles representing LED illumination appear to overlap inFIG. 3, in fact, this overlap results from the imaging of light fromvery brief illumination of the LEDs., and not from the energization timeof the LEDs. The energization of LEDs at the first, second and thirdtimes in each range do not overlap. Therefore, at the most, only threeLEDs are energized at any time (LED5/LED6/LED7 or LED1/LED2/LED3). Atthe middle time in each interval, only LED4 is illuminated, ifenergized.

In the present embodiment LED5, LED6, and LED7 comprise. group 1. Thefeeding of an interval of film 31 triggers the activation of the LEDs ingroup 1. The LEDs in group 1 remain activated for a specified periodafter which they are deactivated. LED 4 comprises group 2 and isactivated immediately after the LEDs of group 1 are deactivated. LED4remains activated for a specified period after which it is deactivated.LED1, LED2 and LED3 comprise group 3 and are activated immediately afterthe LEDs of group 2 are deactivated. The group 3 LEDs remain activatedfor a specified period after which they are deactivated. Thus, only onegroup of LEDs, group 1, group 2 or group 3, is activated at a giveninstant of time.

Referring now also to FIG. 4 the photographing operation begins whenpartial pushdown switch SW1 is activated. First, CPU 57 sends signals toa photometry circuit (not shown) in step S11, directing the photometrycircuit to perform the photometry operation. Details of the photometryoperation are not explained herein. Briefly stated, however, theluminance of an object to be photographed is calculated based on thequantity of light detected by light-sensing elements in the photometrycircuit. The circuit determines the length of time the shutter shouldremain open based on a calculation of luminance.

Next, in step S12, a range finding initiation signal is sent to a rangefinding circuit, which is not shown. Then the range finding operation isperformed.

Next, the position of full pushdown switch SW2 is detected in step S13.If full pushdown switch SW2 is off, the position of partial pushdownswitch SW1 is detected in step S14. If partial pushdown switch SW1 isoff, the photographing operation is terminated in step S15.

If full pushdown switch SW2 is on, the lens is positioned in step S16,according to the range determined in the range finding operation of stepS12. In step S17 the shutter is released for the length of timecalculated in step S11. Next, in step 18, the lens is restored to itsinitial position.

Next, film 31 is advanced, and data is simultaneously imprinted on film31 in step S19. In step S21, the position of partial pushdown switch SW1is determined. Step S21 is repeated until partial pushdown switch SW1 isturned off.

Step S19 consists of one cycle of the film take-up operation. Thisoperation feeds film 31 a distance corresponding to one frame, whereinone frame equals 360 FSS level reversals. As film 31 feeds, the dataimprinting operation is initiated at the 200th FSS edge and continuesthrough the 280th FSS edge.

Referring to FIG. 5, the details of the operation performed in step S19of FIG. 4 are shown. At the start of the film take-up operation calledfor in step S19, a film end detection timer is initiated in step S101.The film end detection timer determines whether the end of the film hasbeen reached. This timer counts down to zero when no FSS level reversalis detected for a specified period. The absence of FSS level reversalsindicates that the film has stopped feeding, and therefore the end offilm is inferred.

Next, a FSS counter is cleared in step S102. The FSS counter counts theFSS level reversals generated by photo interrupter 53, as film 31 isadvanced a distance of 360 FSS reversals corresponding to one frame.Next, forward rotation of feed motor 38 is initiated in step S103. Whenfeed motor 38 is activated, film 31 is advanced and taken up by spool 35of the camera.

In step 104, operation proceeds to S105 if the FSS level has reversed,or to S105 if the FSS level has not yet reversed. In step S105, thelapse of the film end detection timer returns operation to step S104.Otherwise, operation proceeds to step S110. A brake is applied to feedmotor 38 for 100 μs in step S110. Feed motor 38 is halted in step S111.Operation then exits the flow chart of FIG. 5 and returns to step S21 ofFIG. 4.

Referring now also to FIG. 6, if the FSS level has reversed in stepS104, the film end detection timer is cleared, and restarted in stepS106. In step S107, the FSS counter is incremented. Next, in step S108,the value in the FSS counter is compared to the value 200. When thiscomparison indicates that the value 200 is reached, operation proceedsto step S200, where the data imprinting operation is initiated. If theFSS counter does not reach 200, the value in the FSS counter is comparedto the value 360 in step S109.

When the FSS counter reaches 360, advance of a single frame of film 31is completed. If so, a brake is applied to feed motor 38 for 100 μs instep S110. Feed motor 38 is halted in step S111, and the operation exitsthe flow chart of FIG. 5 and returns to step S21 of FIG. 4.

If the FSS counter has not reached 360 upon execution of step S109, theoperation proceeds to step S105, where lapse of the film end detectiontimer is determined. If the lapse is not detected, the operation returnsto step S104. Thus, the operation loops through steps S104 and S105until the film end detection timer has lapsed, or the FSS levelreverses.

When operation branches from step S108 to step S200 upon determinationof a FSS counter value of 200, the film end detection timer is cleared,and the timer restarted in step S202. Next, the FSS counter isincremented in step S203. The FSS counter is compared to the value 280in step S204. If the FSS counter has reached 280, the data imprintingprocess is terminated, and operation branches to step S105 of FIG. 5 andback into the S104/S105 loop.

If the content of the FSS counter is less than 280 at step S204, thedata imprinting process proceeds as follows. The data to be imprinted isread out into the imprinting region of CPU 57 in step S205. In StepS206, control signals for data imprinting are output through controlsignal output terminals C5 and C4 of CPU 57 according to the data readout in step 205. The appropriate LEDs among LED7, LED6 and LED5 of group1 are thus activated. A delay of 100 μs occurs in step S207 during whichthe appropriate LEDs among LED7, LED6 and LED5 remain activated. Afterthe 100 μs delay, the data imprinting signals are terminated in stepS208, and LEDs LED7, LED6 and LED5 are deactivated.

Next, in step S209, control signals for data imprinting are outputthrough control signal output terminal C3 of CPU 57 according to thedata read out in step S205. LED 4 is thereby activated, if appropriate.A delay of 100 μs occurs in step S210 during which LED4 remainsactivated, if appropriate. After the 100 μs delay, the data imprintingsignal is terminated in step S211, and LED4 is deactivated.

In Step S212, control signals for data imprinting are output throughcontrol signal output terminals C2 and C1 of CPU 57 according to thedata read out in step S205. The appropriate LEDs among LED3, LED2 andLED1 of group 3 are thus activated. A delay of 100 μs occurs in stepS213 during which the appropriate LEDs among LED3, LED2 and LED1 remainactivated. After the 100 μs delay, the data imprinting signals areterminated in step S214, and LEDs LED3, LED2 and LED1 are deactivated.

Referring now to FIGS. 1, 3, 5 and 6, the above operation corresponds tothe imprinting of the first column of the dot matrix of the firstcharacter of the data, ie., column A of FIG. 3. This operation iscompleted within the time between two consecutive FSS level reversals.

Referring to FIGS. 2, 3, and 7, FIG. 7 shows the temporal relationshipbetween the FSS and the activation of LEDs LED1˜LED7 to imprint thenumeral "9". At the instant the 200th FSS level reversal is received bythe CPU 57, two of the LEDs in group 1, LED5 and LED6, are activatedwhile the remainder of the LEDs remains deactivated. After the 100 μsdelay, LED5 and LED6 are deactivated. Next, LED4, which comprises group2, is activated. After 100 μs, LED 4 is deactivated, and LED2 and LED3of group 3 are activated. LED1 remains deactivated. LED2 and LED3 aredeactivated after another 100 μs delay. Thus, the first column of thecharacter in FIG. 3 is formed. FIG. 7 shows the timing sequence for theremaining columns that would apply in imprinting the character of FIG.3.

The time delays between imprinting of the successive groups of data,group 1, group 2 and group 3 are evident from the time chart of FIG. 7.The temporally staggered relationship between the imprinting of thethree groups corresponds to the spatial staggering of the characters onfilm 31, shown in FIG. 3, as discussed above.

Thus, before each group of LEDs group 1, group 2 and group 3, isactivated, the other groups are deactivated. Therefore, the maximumnumber of LEDs that may be activated simultaneously is three. If thecurrent required to turn on each LED is 20 mA, a constant-voltagecircuit with a capacity of 60 mA is enough to power LED array 59 of theinvention.

After the imprinting of the first column of data, operation returns tothe loop of Steps S200 and S201. In step S200, the status of the FSS isdetermined. If the FSS level has reversed, operation proceeds to stepS202. If the FSS level has not reversed, operation proceeds to stepS201. Step S201 branches back to node 2 in FIG. 5, if the film enddetection timer has lapsed, or returns to step S200 if it has not.

Referring now to FIGS. 3, and 6, when the FSS level reversal takesplace, corresponding to a FSS count of 201, operation proceeds againthrough steps S202 to S208. Another staggered column of the desiredcharacter, ie., column B of FIG. 3, is thus imprinted. Similarly,columns C, D and E are imprinted at the 202nd, 203rd and 204th FSS levelreversal respectively, completing the imprinting of the first character.

These steps are repeated as above for each character until all thedesired characters have been imprinted. In the present embodiment, theoperation is repeated until the 280th FSS level reversal is counted.

Referring to FIGS. 5 and 6, after the 280th FSS edge is counted, anddata imprinting is completed, the procedure returns from step S204 tostep S104 and the S104/S105 loop of FIG. 5.

Returning to FIG. 2, two of the 5 control signal output terminals, indata imprinting device 10, C2 and C4, of CPU 57 are each connected topairs of control signal input terminals E2/E3 and E5/E6 respectively.Control signal output terminal C2 is connected to control signal inputterminals E2 and E3 and control signal output terminal C4, to controlsignal input terminals E2 and E3. Thus, data imprinting device 10permits the number of control signal output terminals C1˜C5 and controlsignal lines D1˜D5 to be significantly reduced compared with aconventional device.

To be more precise, in the present embodiment, control signals fromcontrol signal output terminals C2 and C4 are passed through signallines D2 and D4, respectively. Signal lines D2 and D4 each input controlsignals to control signal input terminal pairs E2/E3 and E5/E6,respectively. Accordingly, control signal output terminals C2 and C4control LED pairs LED2/LED3 and LED5/LED6, respectively. Therefore, LED2is always activated with LED3 and LED5 is always activated with LED6.

By connecting certain input and output terminals as described, theinvention reduces to five the number of signal lines D1˜D5 compared tothe seven signal lines required in the conventional device.

Another result of the present invention, is that finding sufficientspace to attach signal lines is made easier.

Also, reducing the number of control signal output terminals C1˜C5 ofCPU 57 from seven to five, allows the size of CPU 57 to be reduced. Thismakes it possible to reduce the size and the cost of the entire camera.

The pairing of LEDs as discussed allows imprinting of dot matrixcharacters is show in FIG. 3. Since characters formed in this way aresufficiently recognizable, the device described is as suitable forimprinting data as are conventional devices.

Although the described embodiment called for the pairing of control ofLED2 with LED3 and LED5 with LED6, it is recognized by those skilled inthe art that other pairings are possible. Such other combinations may beemployed without departing from the scope or spirit of the invention asdefined in the claims.

Although seven LEDs are used in the embodiment described above, thenumber of LEDs is not limited to seven. Any convenient number of LEDsmay be used for representing characters without departing from the scopeor spirit of the invention as defined in the claims.

Furthermore, in the described embodiment, data is imprinted in the formof numerals. However, it is recognized by those skilled in the art thatthe invention may be applied to the imprinting of other types ofcharacters. For example, the invention may be applied to the imprintingof alphabet, the Japanese syllabary, such as hiragana and katakana, andChinese characters, without departing from the scope or spirit of theinvention as defined in the appended claims.

Moreover, in the described embodiment, signal lines D2 and D4 wereconnected to pairs of control signal input terminals E2/E3 and E5/E6.However, it is recognized by those skilled in the art that a singlesignal line may be connected to three or more control signal inputterminals without departing from the scope or spirit of the invention asdefined in the claims.

Furthermore, the possible grouping combinations of LEDs is not limitedto those described above. Other combinations may be employed if eachgroup comprises LEDs that are adjacent to each other. However, thenumber of LEDs in a group should be set considering the slanting effectincurred. Very few LEDs per group would cause the characters imprintedto be too slanted, as in the prior-art reference noted in the backgroundsection hereof. Many LEDs per group would diminish the advantageobtained in reduction of peak demand on the constant voltage circuit.Light emitting elements other than LEDs may be employed withoutdeparting from the spirit and scope of the invention.

The invention described may reduce considerably, the number of controlsignal terminals and lines, and power demand of a camera data imprintingdevice. Thus, the size and cost of the CPU, the number of signal lines,and the size, complexity and cost of the constant voltage circuitelements are reduced compared to conventional devices.

Additionally, the present invention imprints characters that are lessslanted than those imprinted by prior art devices that employ temporalstaggering of the LEDs. For example, Japanese Laid-open PatentPublication No. 4-81831, obtains a lower peak power requirement byactivating the LEDs sequentially, and activating successive LEDs beforethe previous ones are deactivated. However, in this device, thecharacters imprinted are very slanted and difficult to read.

Having described preferred embodiments of the invention with referenceto the accompanying drawings, it is to be understood that the inventionis not limited to those precise embodiments, and that various changesand modifications may be effected therein by one skilled in the artwithout departing from the scope or spirit of the invention as definedin the appended claims.

What is claimed is:
 1. A data imprinting device for a cameracomprising:a plurality of light emitting elements including at leastfirst and second groups, at least one of said at least first and secondgroups having at least two light emitting elements therein; a controlcircuit; said control circuit including a first sub-circuit whichproduces at least a first control signal and a second control signal; afirst device, responsive to said first control signal, which controlssaid first group of said plurality of light emitting elements; a seconddevice, responsive to said second control signal, which controls saidsecond group of said plurality of light emitting elements, independentlyof said first group of said plurality of light emitting elements; andsaid control circuit including a second sub-circuit which controls saidfirst control signal at a time non-overlapping with a timing ofcontrolling of said second control signal, whereby reduced peak powerdemands are provided.